I feel that telling a man to "work on himself" in order to make himself a more attractive prospect has a lot merit for a significant number of men in the real world.
Let's face it, a significant of men are overweight and out of shape, you don't think encouraging someone like this to exercise, eat better and take care of himself wouldn't make things easier.
A lot of guys are "boring" and have no hobbies, interests, unique skills, etc. Telling a guy to learn to play the guitar, take up yoga, scuba diving, etc. may not directly land him women but it will provide him with an assortment of benefits. This will give this man a "life" and will get him out around other people with similar interests, some of whom may be women that he'd have something in common with.
A lot of guys work in mundane positions, many of which do not pay that well. Telling a man in a position like this to better himself by getting a degree, pursuing a career he has an interest in will indirectly help. This wouldn't necessarily be due to having more money but because he is showing that he has drive and ambition, can work towards goals and accomplish them, all of which are attractive traits to have.
Men should be encouraged to better themselves and work on self improvement, not specifically to get women but just for them to live a better life.
Now, if a man has done things to better himself and has made his life a work in progress but is still having issues with women there are other things that need to be addressed. Perhaps he simply is just not around enough women or in situations where meeting them is realistic. Perhaps he lacks the social skills/confidence to do well with women, especially if he also isn't around them much at all to begin with.
We also need to accept that some men will just never be able to do well with women no matter what they do with themselves, a result of a wide variety of factors that may or may not be beyond their control.